The fuel cell system described in JP2007-517369A includes a normally-closed solenoid-operated valve in an anode gas supply passage and a normally-opened solenoid-operated valve and a buffer tank (a recycle tank) in series from upstream in an anode gas discharge passage.
This conventional fuel cell system is an anode gas non-recycling fuel cell system which does not return unused anode gas discharged to the anode gas discharge passage to the anode gas supply passage, carrying out the pulsation operation to increase or decrease a pressure of the anode gas with a width of the pulsation in accordance with the operational status by means of a control valve for controlling the anode pressure.